The Advanced Clean Cars Program includes a goal of putting more hybrid and zero-emission vehicles on California's roads

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Testimony on the California Air Resources Board's "Advanced Clean Car'' program -- new rules that would require major changes for automakers by 2025 -- began Thursday in front of regulators in Los Angeles.

The new rules would require automakers to build cars and trucks that emit about three-quarters less smog producing pollutants. The program also calls for an increase in the number of hybrid and zero-emission vehicles on California's roads.

The regulations would affect model years 2017 through 2025.

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During testimony Thursday, the board's chair said the goals will help California "lead the nation and the world" in efforts to reduce smog-producing pollutants. More testimony is expected Friday about an issue on which California has been out front, a position that presented challenges the last time the state developed greenhouse gas standards.

He was referring to legal challenges from auto dealers and business groups after the state passed the initial greenhouse gas emissions limits.

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"They sued us in two federal courts," Cackette said. "Fortunately, from our viewpoint, they lost. Over that time, with the increase in gas prices, the shake-up in the auto industry brought new management which looked at the future. Where's our future? It's not profits next quarter but how do we make a sustainable business."

California's first-in-the-nation standards for cars and truck went into effect in 2009. Fourteen other states have adopted California's emissions goals, which are usually more stringent than federal standards.

The latest proposals on greenhoue gas emissions were created with federal regulators to match national standards expected to be passed later this year.

The plan to put more zero-emission and plug-in hybrids on the road sets a goal of 1.4 million such vehicles by 2025. It even sets goals as far out as 2050.

"This regulation is planned over a 40-year horizon, and that is extremely unusual,'' board spokesman David Clegern told the AP. "But it gives us time to put the pieces in place with no surprises. The individual companies can plan for changes and develop the technology, and over the long haul, it will shift us away from reliance on petroleum.''

Hybrids make up about 4.1 percent of California's market, according to the California New Car Dealers Association.

Earlier this week, federal regulators were in San Francisco to hear public comment on the Obama administration's national fuel economy standards. They would require the average passenger car to reach a 54.5-mph standard by 2025.

As for how higher standards might affect consumers, Forrest McConnell, director of the National Automobile Dealers Association, testified during the Tuesday hearing that more expensive cars would price people out of the market.

"We all want better fuel economy, but it is not free," McConnel said.

The air board argues the money saved on fuel costs must be considered.